Signal lights are often used to indicate to observers the location of the signal light user. One particular application of signal lights is to indicate to delivery or emergency vehicles a particular address or location at which a delivery is to be made, or at which emergency services are to be rendered. Such lights are useful since it may be difficult for delivery or emergency personnel to locate a specific address for a residence or business, particularly in low light conditions where the personnel are in a hurry, and where addresses may not be prominently posted at a location. A summary of several prior signal lights which were specifically designed to attract delivery or emergency personnel follows.
U.S. Pat. No. 5,103,581 to Novak describes a signal light (a “delivery alert apparatus”) which is intended to be turned on and visibly placed outside a location where a delivery is to be made (e.g., a pizza delivery), so that the delivery personnel can more rapidly identify to where the delivery is to be made. As detailed in column 3 of the patent, the device has a casing in the form of a thick disc with a hanging strap/loop at its top. When a switch on the rear of the casing is activated, batteries illuminate a bulb within the casing. The bulb transmits its light through fiberoptic cables having terminal ends arrayed through apertures in the front face of the casing to form letters. Thus, for example, the front face of the device's casing could display illuminated letters spelling the message “PIZZA BUDDY.”
U.S. Pat. No. 6,098,326 to Campbell describes a signal light for drawing attention to a location for deliveries, emergencies, and the like. The device has an elongated box-like casing which may be hung at its top from a hanging strap/loop (see FIG. 2), and a translucent front sign panel (which may bear an opaque message thereon) is inserted into a slot at the front of the casing to define its front surface (see column 4 lines 30-50). The sign panel is interchangeable with other sign panels bearing different messages. Incandescent lights within the casing illuminate the sign panel from its rear when powered from a power cord, and a switch on the casing allows a user to set the lights in constantly on, blinking, and off modes (column 4 lines 9-18). Light is also projected through holes in the top of the casing (column 3 lines 16-26).
U.S. Pat. No. 4,686,505 to Vanderburg describes a signal light similar to the one of Campbell (discussed above), but here the casing has two compartments, one bearing the sign panel at its front (with the sign panel bearing address numbers), and the other containing a strobe light which flashes adjacent the sign panel (see FIG. 1). The device bears slotted holes on the rear of the casing so that fasteners protruding from a building may be inserted therein to support the casing (column 2 lines 40-45). While the strobe and sign panel lights are described as being powered by a cord, batteries are also contemplated (column 3 lines 6-8).
U.S. Patent Application Publication 2002/0070929 to Hunter describes a signal light similar to the one of Vanderburg (discussed above), but as shown in FIG. 1 and described at paragraphs 0014-0015, the front sign panel (which may bear a message such as “HELP”) is intended to flash, and rotating or flashing dome lights are also provided atop the casing. A siren may also be provided on the device (paragraph 0005). The device is intended to be actuated by a wireless signal, which may selectively activate one or more of the siren, the front sign panel illumination, and/or the dome lights (paragraph 0017). The device can be mounted on a wall of a building, or on a pole (paragraph 0013, 0016).
U.S. Pat. No. 4,611,265 to Davis describes a lighted address display including a flashing emergency signal light. The display has an elongated box-like casing with a translucent face plate, with address numbers/letters being formed of opaque material and being applied to the face plate (column 3 lines 25-27). As illustrated in FIG. 4, one bulb within the casing is activated by a photocell during low light conditions, and the flashing bulb within the casing may be activated by a remote switch, which may be a wireless switch (column 3 lines 37-42).
U.S. Pat. No. 4,839,630 to Miller describes an emergency signal light which is provided in accompaniment with a loud horn, and which can be mounted on a wall (column 3 lines 15-29). Power is provided by standard household current or by batteries pack (column 3 lines 24-26, column 5 lines 3-8). Referring to FIG. 2, the light/horn can be activated by pushing a switch 88 situated at the end of an extension cord 9, with the switch having an adjacent LED 91 which indicates when the light/horn are activated. Activation of the switch can also complete a phone dialing circuit to dial an emergency number (column 4 line 60 onward). The light may be made to flash if desired (column 5 lines 46-49).
U.S. Pat. No. 6,000,811 to Bordak describes a portable signal light for signaling home or roadway emergencies having a generally cylindrical casing with red and white flashing lights at its opposite ends (FIG. 1, column 2 lines 55-63). A hanging strap/loop is provided to allow the signal light to be hung on a doorknob or the like (column 3 lines 54-59). Each light is powered by one or more batteries within the casing, and is activated by its own independent switch (column 3 lines 12-31).
There also signal lights designed for other applications. As an example, U.S. Pat. No. 5,893,626 to Poling describes a signal light which is suitable for attachment to a bicycle or other vehicle. The light includes a casing which contains batteries (though attachments to external power supplies may be used, column 3 lines 57-60), and a switch on the casing powers lights situated behind a transparent face on the casing (column 4 lines 2-6). The lights, which are arranged in concentric rings and which may be provided in different colors, may be incandescent bulbs or LEDs (column 4 lines 5-37). The central light may be on constantly or may blink (column 4 lines 38-49), whereas the outer rings of lights may sequentially illuminate in a circular pattern, but with each ring illuminating in an opposite direction (column 4 lines 50-67). Two versions of the signal light are illustrated, one being of a cylindrical shape conventional for bicycles and similar vehicles (FIG. 1) and which may be attached to a vehicle by use of a bracket, straps, magnets, or other arrangements (column 3 lines 61-65), and the other being of a disc-like shape (FIG. 5) which is intended to be worn by a user by use of a wrist strap, neck cord, or the like (column 5 line 53-column 6 line 6).
Despite the prior work in the field of signal lights for attracting delivery or emergency personnel, such signal tights are rarely used owing to certain deficiencies. Initially, they are often not very visible, and therefore are not very effective. As an example, devices such as U.S. Pat. No. 5,103,581 to Novak—wherein some particular message is illuminated—are often ineffective since the signal light is observed from such a distance that the characters of the message appear as an illuminated blur. In effect, from a distance, the message simply appears as a unitary light, which is indistinguishable from a common house, business, vehicle, or street light. Flashing lights can help make a signal light more distinctive with respect to lights commonly encountered in the surrounding environment, but even these can be difficult to differentiate from flashing vehicle or business lights. Low frequency flashing may also be unnoticeable to delivery or emergency personnel who are in a hurry, since they may only glance at the area where the signal light is located, and do so when the light is either on or off, in effect causing the personnel to miss the fact that the light is flashing.
Additionally, cost, maintenance, and installation issues have precluded the wide use of signal lights. Several of the aforementioned signal lights are bulky and expensive, and require hardwiring or other significant installation steps such that the burdens of their installation and use outweigh their benefits. Other signal lights are designed to be portable self-contained units having battery-based power supplies, but even these tend to be so bulky and expensive that most consumers do not regard them as being worthwhile to obtain, particularly since they are generally not used on a frequent basis. Many consumers find it difficult to store a flashlight in a convenient, ready-to-use location, and since the prior signal lights effectively constitute special-use flashlights (generally of large size), most consumers simply don't care to purchase and store the prior signal lights: they represent a rarely-used piece of electronic equipment which is simply not worth the storage space that it occupies. The signal lights are also inconvenient to maintain, particularly where they use common incandescent bulbs and standard A, C, or D-cell batteries. Incandescent lights rapidly consume power and require frequent battery replacement, which is particularly true where the incandescent lights flash (which also tends to cause rapid bulb deterioration and the need for frequent bulb replacement).